Impact hammer crimping tool



Feb. 11, 1969 I o. c. WILSON, JR

IMPACT HAMMER CRIMPING TOOL Filed June 24, 1966 INVENTOR. (2. 10/480, c/

4 TTOE/VAE'YS.

United States Patent 3,426,573 IMPACT HAMMER CRIMPING TOOL .0. C. Wilson, Jr., Shreveport, La., assignor of one-half 8 Claims ABSTRACT OF THE DISCLOSURE An impact-operated sheet metal crimping tool consisting of a sleeve with a striking plunger slidably disposed therein. The plunger has an enlarged impact head at its-bottom end receivable in the sleeve and limited in its upward movement by an internal stop collar fixed in the sleeve. The plunger has a driving shank at its top end. The plunger is biased upwardly by a coil spring. The bottom end of the sleeve is angled and is formed with notches shaped to engage on the interengaged end flanges of pieces of sheet metal to be joined to form desired crimps therein.

This invention relates to impact hammer-operated tools, and more particularly to a tool of this kind which is especially, but not exclusively, for use in closing and crimping seams of sheet metal forms, such as air conditioning ducts, and the like.

The primary object of the invention is the provision of a simple and mechanically sound tool of the character indicated above, by means of which seams of metal forms can be efiicien'tly, quickly, and economically closed and crimped.

In the drawings:

FIGURE 1 is a perspective view, partly broken away and in section, of a tool of the present invention, showing its plunger in retracted position;

FIGURE 2 is an enlarged vertical transverse section, taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary schematic perspective view, on a reduced scale, showing the tool applied to crimp the seam joining two fiat metal forms; and,

FIGURE 4 is a view, like FIGURE 3, showing the tool applied to crimp the seam of an air conditioning duct.

Referring in detail to the drawings, the illustrated device comprises a relatively stationary, vertically elongated tubular cylindrical housing having an open upper end 12 and a lower end 14. As shown in FIGURE 2, the lower end 14 of the housing 10 is disposed at an acute angle to the horizontal, and has a high side 16 and a low side 18. The low side '18 of the lower end 14 is centrally formed, as indicated in FIGURES 2 and 3, with a symmetrical notch 20. The notch 20 is sized and shaped to conformably receive the upper flange 22 of a lock seam 24 connecting together adjacent edges of flat sheet metal forms 26 laid upon a supporting surface (not shown).

The lower end 14 of the side wall 28 of the housing 10 is formed, preferably at distances of about 90 degrees from the center of the notch 20, with V-shaped notches 30 having straight vertical sides 32 and acutely angulated sides 34. The sides 32, as shown in FIGURE 2, are in the vertical plane of the axis of the housing 10. As shown in FIGURE 4, in closing and crimping the seam 36 of an air conditioning duct 38, the seam being of the type known as a Pittsburg lock, the straight sides 34 of the notches 30 are applied to the outer side of the free edge portion 40 of the outer flange 42 of the seam 36, with the angled sides 34 of the notches 30 applied to the outer side of the flange 42 so that the portion 40 is maintained in proper relation to the flange 42 as the plunger of the tool descends and strikes the portion 40 and crimps the same onto the upper surface of the adjacent horizontal wall 44 of the duct, the duct being supported in these operations upon a suitable support, not shown.

The housing 10 is internally formed with or is suitably provided with an internal sleeve 46, shorter than and spaced from the ends of the housing 10. The sleeve 46 serves as a spacer for a plunger 48 relative to the housing 10 as a bearing for the plunger and as a stop for an enlarged diameter striking head 50 on the lower end of the plunger. As shown in FIGURE 2, the lower end 52 of the sleeve 46 is spaced at a substantial distance above the notches 30.

The plunger 48 has a plane cylindrical body '54 of a length substantially greater than the distance between the lower end 52 of the fixed sleeve 46 and the upper end 12 of the housing 10. The plunger head 50 is small enough in diameter so that its free edge 56 has clearance with the side wall of the housing 10. The head 50 has a rounded lower edge 58. The main body 54 of the plunger terminates at its upper end in an upstanding reduced diameter axial shank 60 dimensioned to fit in the chuck of an impact hammer (not shown).

An annular external snap ring groove 62 is formed at the upper end of the plunger body 54, in which is engaged a removable snap ring 64, which serves as a stop for a retainer ring 66'.

The retainer ring 66 slides on the body 54 of the plunger and has an internal groove 68 at its top, which engages and receives the lower side of the snap ring 64. The retainer ring 64 is formed with an external groove 70 in its bottom, the groove 70 being spaced from the opening of the ring 64, so as to define a spacer shoulder 72.

A coil plunger retracting spring 74, larger in diameter than the body 54, of the plunger 48 is spacedly circumposed thereon and is compressed between the upper end 76 of the housing sleeve 46 and the retainer ring 6 4, the upper convolution 78 of the spring being engaged in the retainer groove 70, whereby the plunger 48 is normally in an upwardly retracted position relative to the housing 10.

'In operation, the plunger shank 60 having been engaged in the chuck of an impact hammer, and the related notch or notches of the housing 10, having been applied to the work, the action of the: hammer drives the plunger 48 downwardly in the housing against the resistance of the spring 74, and applies the striking head 50 to the work. As the operating component of the hammer retracts, the spring 74 acts to retract the plunger 48 relative to the work and relative to the housing 10 preparatory to another working stroke.

What is claimed is:

1. A tool of the character described, comprising a tubular housing having upper and lower ends, a sleeve fixed within said housing and spaced from the ends of the housing, a plunger sliding through said sleeve, said plunger having an enlarged work striking head on its lower end and a reduced diameter shank on its upper end, said shank extending above the housing, and spring means normally retracting the plunger upwardly in the housing, wherein the housing has a sidewall, the sidewall at the lower end of the housing being formed with work-receiving notch means.

2. The tool of claim 1, wherein said notch means comprises diametrically opposed notches.

3. The tool of claim 1, wherein the lower end of the sidewall is disposed at an angle to the horizontal, and having a high side and low side.

4. The tool of claim 1, wherein the lower end of the sidewall is disposed at an angle to the horizontal, and having a high side and a low side, said notch means being formed in said lower end of the sidewall.

5. The tool of claim 1, wherein the lower end of the sidewall is disposed at an angle to the horizontal, and having a high side and a low side, said notch means being formed in said lower end of the sidewall, said notch means comprising a single centered notch in said low side.

6. The tool of claim 1, wherein the lower end of the sidewall is disposed at an angle to the horizontal, and having a high side and a low side, said notch means being formed in said lower end of the sidewall, said notch means comprising diametrically opposed notches formed in said lower end at locations intermediate the said high and low sides.

7. The tool of claim 1, wherein said striking head is smaller in diameter than the housing and the lower end of the sleeve serves as a stop for said head, said plunger having a body working in the sleeve, said body being formed at its upper end with a snap ring groove, a snap ring engaged in said groove, a retainer ring circumposed on said body and engaged with the underside of the snap ring, said spring means being a coil spring circumposed on said body and compressed between the upper end of the sleeve and the underside of the retainer ring.

8. The tool of claim 1, wherein said striking head is smaller in diameter than the housing and the lower end of the sleeve serves as a stop for said head, said plunger having a body working in the sleeve, said body being formed at its upper end with a snap ring groove, a snap ring engaged in said groove, a retainer ring oircumposed on said body and engaged with the underside of the snap ring, said spring means being a coil spring circumposed on said body and compressed between the upper end of the sleeve and the underside of the retainer ring, said coil spring being smaller in diameter than the housing and larger in diameter than the plunger body, said retainer ring being formed in its underside with an annular groove spaced from the opening of the retainer ring, said spring having a top convolution retainably engaged in said annular groove.

References Cited UNITED STATES PATENTS 1,233,560 7/ 1917 [Dilfendall 279-4916 1,409,230 3/ 1922 Moses 17=31Q0 2,547,391 4/ 1951 Hauscild 7 2-479 CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 

